When an abnormality such as a failure to release a resource by a program employing a semaphore occurs, an operation manager has to promptly identify a cause of the abnormality in order not to allow the abnormality to affect a service provided for a user. In obtained trace information (log information), however, there are a large number of pieces of trace information that have been obtained while the program has been operating normally. It might therefore take a long time for the operation manager to identify trace information including information regarding the abnormality during investigation of the cause of the abnormality. In addition, because memory capacity for storing trace information is limited, the obtained trace information might not be stored for a sufficient period of time.
For this reason, older trace information is removed from a storage unit. In addition, in order to efficiently obtain trace information used for an investigation, a method has been proposed in which if it is determined that all monitoring targets are not using a certain resource, trace information is removed from the storage unit. Japanese Laid-open Patent Publication No. 2016-18470, for example, discloses one of such techniques.